Electrical transformer



(No Model.)

- P. ZIOKERMANN.

ELEGTRIGAL TRA-NSFORMER.

No.529, 152. I PatentedNov.13,-1894.

IN VENT OR BY 2 ATTORNEY THE mumps virus 0 mmoumo wnsmnarou, u. d.

NrTED STATES PAT NT QFFICE.

FRITZ ZIOKERMANN, OF BERLIN, GERMANY, ASSIGNOR TO SIEMENS 82;

I HALSKE, OF SAME PLACE.

ELECTRICAL TRANSFORMER.

SPECIFICATION forming part of Letters Patent No. 529,152, dated November13, 1894.

Application filed December 9, 1892. Serial No. 454,652, (Nomodel-JPatented in Germany October '7, 1892, No. 73,200; in France October31,1892, No. 225,299; in Switzerland October 31, 1892, No. 5,93 inEngland November 3,1892,No. in B lgi m November 7, 1892, No. 102,009,and in Italy April 28, 1893, No- 34,011.

T0 at whom it may concern.-

Be it known that I, FRITZ ZIGKERMANN, a subject of the King of Prussia,German Ell].- peror, residing at the city of Berlin, Kingdom of Prussia,German Empire,'have invent-ed new and useful Improvements inTransformers, (for which Letters Patent have been obtained in England,No. 19,821, dated Novemb613,1892; in Germany, No. 73,200, dated October7, 1892; in France, No. 225,299, dated October 31, 1892; in Belgium, No.102,009, dated November 7,1892; in Italy, No. 34,011, dated April 28,1893, and in Switzerland, No. 5,934, dated October 31, 1892,) of whichthe following is a specification.

My invention consists of a transformer so constructed that its currenttransforming capacity may be altered without changing the potential ofthe current from the source of energy, the potential of the current fromthe secondary terminals, or the translative relation of its elements.

The object of my invention is threefold;

First, to provide for the varying demand for current in the secondarydistributing circuit fed from the transformer; second, to reduce theconsiderable loss of energy now occurring in distribution systemsemploying transformers, and due to the fact that the energy required tomagnetize the core of a transformer as now constructed is a constantfactor, irrespective of the work in the secondary circuit; third, topermit the capacity of the transformer to be instantaneously alteredwhile in operation without causing any disturbance in the system inwhich it is included.

In electrical distribution systems employing transformers, it has beendetermined by observation that the maximum transforming capacity of atransformer is only required for 1.5 hours in twenty-four, and that thecurrent required to magnetize the core amounts to three per cent.of thetotal energy. Hence, the present practice, where transformers areemployed having constant windings, entails a loss 0 3 which equalsforty-eight per cent. of the total energy. Where a transformer isconstructed according to my invention, this loss, due to themagnetization of the core, is almost entirely avoided, for reasons whichwill hereinafter be fully explained.

In designing my improved transformer, I make use of the fact that with aconstant potential at the primary terminals, its current convertingcapacity depends upon the number of lines of force threading the core,and that the number of lines of force is inversely proportional to thenumber of turns or windings of the primary coil of the transformer.Hence, it follows, that, if a transformer be constructed with a certainsize of conductors and definite number of turns on its primary andsecondary coils, and the size and number of turns of the respectivecoils are so determined that the loss of potential, and that due to themagnetization of the core, have their usual value, certain definitetranslative relations will exist, and a current of a certain potentialand quantity can be obtained from the secondary terminals; and, if thenumber of turns of the conductors of both the primary and secondarycoils be correspondingly increased, the translative relations will notbe altered. The same potential will exist at the secondary terminals,but the quantity of current delivered will decrease. Thus, for instance,by doubling the number of turns of both the primary and secondary coils,while preserving the potential of the current constant in the primary,the current will bedecreased in proportion to the number of lamps incircuit, while the translative relations will remain the same. At thesame time the energy used to magnetize the core will be onethird of thatrequired with half the number of turns.

To carryoutthe principles above set forth,- that is toconstructatransformer in such manner that the turns may besimultaneously added to or subtracted from the primary and secondarycoils,presents mechanical difficulties. The same result, however, may beaccomplished by making use of the arrangement shown in the accompanyingdiagram,in which the numberof turns of both the primary and secondarycoils is maintained constant, but

their connection to their respective primary and secondary circuits isaltered; that is, the independent sections of both the primary andsecondary coils are connected in parallel in their respective circuitsfor such time when the greatest transforming capacity is required,whereas, the independent sections of the primary and secondary coils arecoupled in series and across the respective circuits, when theconsumption in the distribution circuit is the smallest.

The accompanying diagram will serve to more fully explain my invention,and in which 5 indicates an alternating currentgenerator of any suitableconstruction; 6 and 7,feeder conductors; 9 and 10, conductors of thedistributing circuit; 11, translating devices, such as lamps connectedin parallel in the distributing circuit; 12, an alternating currenttransformer interposed between the feeder-and distributing circuit.

The transformer as shown consists of a closed magnetic core 13, made upof laminated plates of soft iron. The primary and secondary coils areeach shown as composed of two sections 14-14 1515, and such coils arewound upon the core of the transformer in the usual manner. The ends ofthe section 14 of the primary coil are connected through the conductors16--16, with the binding posts 1717. The section 15 of the secondarycoil is similarly connected through two conductors 18-1S with thebinding posts 1919.

The conductors 6 and 7 are at one end connected tothe brushes bearing onthe collecting rings of the generator, and at their other ends, theconductor 6 to the beginning of coil 14 and the conductor 7 to the endof coil 14 and also to the contact point 20. The upper end of the coil14 is connected to contact point 20. The connection between theconductors 9 and 10 and the coils 1515, and the conductors 18-18 andcontact points 21-21 are made in a similar manner.

22 represents a plate of insulating material which connects the switchplates 2323, by means of which the plates may be simultaneously shifted.When the switch plates 2323 are inthe position shown in full lines, thetwo sections of the primary coil are in parallel of the conductors 6 and7, and the two sections of the secondary coil in parallel of theconductors 9 and 10.

The path of the primary current (parallel connection) is then asfollows: By conductor 6 through coil 14, conductor 16, post 17, plate23, point 20, conductor 7, to generator. The current from 6 divides andpasses through the conductor 16 to point 17, plate 23, point 20,conductor 6, coil 14:, conductor 7, back to generator. When the twosections of each coil are coupled in parallel, it will be observed thatthere are two paths for the current, and in each path there is a sectionof the primary coil of eight turns, and in the secondary coil of fourturns; thus showing that the ratio of conversion is 8:4:2z1, but asthere are two paths there is a double cross-section of conductors, andfour times the current flows.

WVhen it is desirable to reduce the capacity of the transformer and themagnetization of the core, as is advisable at times of small consumption in the distribution circuit, the switch plates 23-23 areshifted to the position shown in dotted lines, in which case bothsections of each coil are thrown into series and the whole coil acrossthe circuit to which it is connected.

The path of the primary current (series connection) is as follows:Conductor 6, coil 14-, conductor 16, post 17, plate 23, point 20,conductor 6, coil let, conductor 7, back to generator. The primary coilthen consists of two by eight turns equals sixteen turns,-all of theturns being in series,-and the secondary coil two by four turns equalseight turns, also in series. Thus, while it will be observed that thereis the same number of turns that there was before in the primary andsecondary coils, there are in elfect twice as many turns in the singlepath of the current, and the ratio of conversion is the same, that is,sixteen is to eight es two is to one. The connection of the primary andsecondary coils to their respective circuits is substantially the same.It is therefore unnecessary to give the path of the secondary currentfor parallel or series connection.

Theoretically, the number of lines of force generated in the iron coreby this duplication of the number of turns in a single circuit isreduced one-half, the potential at the secondary terminals remaining notexactly, but practically constant, and at the same time the energy lostin magnetizing the core is reduced to one-third of what it was when thecoils were in parallel, since the energy lost is proportional to M 2,,'i. a, one-sixth power of M (lines of force.)

The essential characteristic of the present invention it will thereforebe observed is, that if the number of turns of the primary and secondaryelements included in a single primary and secondary circuit besimultaneously increased or decreased, such change acts to vary thetransforming capacity of the device, as also the amount of currentrequired to magnetize the core, without in any wise altering thetranslative relations of the elements of the transformer.

The principle embodied in my improvement in transformers may be utilizedin converting single phase or polyphase currents. Further, my inventionis not limited to a transformer having its primary and secondary coilsdivided into two sections. There may be any number of sections, it beingunderstood that by increasing the number of sections the capacity'of thetransformer may be step by step varied from minimum to maximum load, andvice versa.

I wish it understood that I do not limit myself in any wise to theembodiment of my invention illustrated and described in the pres IIO cutapplication, as various other constructions may be made which willfullycomply with the intent of my invention.

Having thus described my invention, I claim 1. A transformer consistingof the core, a primary element, a secondary element, and means forsimultaneously increasing or decreasing the number of the turns inseries of the coils which form the primary and secondary elements,substantially as and for the purpose set forth.

2. A transformer consisting of a core, a sectional primary element, asectional secondary element, and means for simultaneously increasing ordecreasing the number of sections of each element in series,substantially as and for the purpose set forth.

3. A transformer consisting of a core, a sec tional primary element, asectional secondary element, and means for simultaneously connecting thesections of the primary element in parallel of the primary conductors,and the sections of the secondary element in parallel of the secondaryconductors, or the sections of the primary element in series and acrossthe primary conductors and the sections of the secondary element inseries and across the secondary conductors, substantially as and for thepurposes set forth:

4. A transformer consisting of a core, a sectional primary element, asectional secondary element, and means for simultaneously altering thenumber of sections of the primary element in a single circuit across theprimary conductors, and the number of sections of the secondary elementin a single circuit across the secondary conductors, and in such amanner as not to alter the translative relation of said elements.

5. In a system of electrical distribution, the combination with agenerator of electricity, a feeder circuit and a distributing circuit ofa transformer interposed between the two, said transformer comprising acore, sectional primary and secondary coils thereon, and means forsimultaneously altering the relation of said coil sections to the feederand distributing circuits while maintaining their translative relationsto each other.

6. In a system of electrical distribution, the combination with agenerator of electricity, a feeder circuit and a distributing circuit,of a transformer interposed between the two, said transformer comprisinga core, sectional primary and secondary coils thereon, and means forsimultaneously altering the relation of said coil sections to the feederand distributing circuits without altering the absolute number of turnsof said coils and their translative relations to each other.

7. The combination in a transformer of a core, a primary element, asecondary element, and a device, for varying the resistance of saidelements by simultaneously increasing or decreasing the number ofampere-turns of the respective elements.

8. The herein described method of varying the energy required tomagnetize the core of a transformer which consists in simultaneouslyvarying the number of ampere-turns of the primary and secondary elementsof said transformer.

9. The herein-described method of regulating the capacity of atransformer, which consists in varying the number of lines of forcethreading the core while maintaining the potential of the primary andsecondary elements and their translative relations constant.

10. The herein-described method of regulating the capacity of atransformer, which consists in varying the number of lines of forcethreading the core by Varying the current in the primary element of saidtransformer while maintaining constant the potential of the primary andsecondary elements, the number of coil sections forming said elements,and the translative relations of said elements.

In testimony whereof I have affixed my signature in the presence of twowitnesses.

FRITZ ZICKERMANN. Witnesses;

GUSTAV STENZEL, MAX WAGNER.

